Current non-contacting torquemeters are incapable of measuring torque in rotating shafts with accuracy when there is relative motion between a shaft and a transducer assembly. Furthermore, existing torquemeters lack the ability to self-calibrate, requiring in situ or periodic calibration, and have low overall reliability.
There are existing torque and alignment sensors that can address some of these issues. For example, in one existing configuration, multiple sensors are used to measure the timing of two separate toothed target wheels that provide measurements of three degrees-of-freedom of articulation including measurements of twist and angular misalignment. Such an arrangement can provide nearly unparalleled torque measurement accuracy, as well as alignment measurement. This highly reliable sensor is non-contacting and has minimal impact on shaft dynamics, but such a system requires the use of an array of sensors arranged at multiple positions about the measured shaft, and extensive signal processing is needed used to achieve the torque and alignment measurements.
As a result, it would be desirable for a non-contacting torquemeter to be able to measure torque in a rotating shaft with improved accuracy in the presence of relative motion between a rotating shaft and a transducer assembly. It would further be desirable for such a non-contacting torquemeter to have improved robustness and reliability, and to be able to self-calibrate. In addition, it would be advantageous for the non-contacting torquemeter to be able to provide accurate torque measurements using a single transducer assembly positioned at a single azimuthal position on a rotating shaft.